1. Field of the Invention
The present invention relates to a seesaw switch performing the switching operation by tilting an operating lever around a supporting shaft in both directions with respect to the supporting shaft, and more specifically to a seesaw switch with double action capable of performing double switching operations along with click feelings by tilting an operating lever in one direction.
2. Description of the Related Art
FIG. 6 is a sectional view showing a prior art seesaw switch with double action of this type, which has been disclosed in Unexamined Japanese Utility Model Publication No. SHO 60-35442. In this figure, reference numeral 1 indicates an operating lever, which is supported so as to be rockable in both the directions of the arrows A and B around a supporting shaft 2. Four pressing portions 1a, 1b, 1c and 1d are hangingly provided on the back surface of the operating lever 1, wherein the two pressing portions 1a and 1b are provided on the right side of the supporting shaft 2 and the two pressing portions 1c and 1d are provided on the left side. Reference numeral 3 indicates a click rubber composed of a silicon rubber or the like, which is mounted on a printed circuit board 4. The click rubber 3 is provided with four projecting portions 5, 6, 7 and 8 corresponding to the pressing portions 1a to 1d, respectively. Movable contact points 5a, 6a, 7a and 8a are provided on the lower surfaces of the projecting portions 5, 6, 7 and 8, respectively. On the vertexes of the two projecting portions 5 and 7 located on the inner side, cylindrical portions 5b and 7b are respectively formed in such a manner as to be respectively elastically contacted with the lower surfaces of the pressing portions 1a and 1c. On the contrary, the two projecting portions 6 and 8 located on the outer side are respectively opposed to the lower surfaces of the pressing portions 1b and 1d with specified intervals. Further, fixed contact points 1a, 1b, 1c and 1d are provided on the surface of the printed circuit board 4 so as to correspond to the movable contacts 5a, 6a, 7a and 8a, respectively. The movable contact point 5a and the fixed contact point 4a form a first switch S.sub.1 ; the movable contact point 6a and the fixed contact point 4b form a second switch S.sub.2 ; the movable contact point 7a and the fixed contact point 4c form a third switch S.sub.3 ; and the movable contact point 8a and the fixed contact point 4d form a fourth switch S.sub.4.
In the seesaw switch thus constructed, the operating lever 1 is usually applied with an elastic force from both the cylindrical portions 5b and 7b of the click rubber 3 to be held at the neutral position shown in FIG. 6. In this case, the first to fourth switches S.sub.1, S.sub.2, S.sub.3 and S.sub.4 are all in the off-state. When the operating lever 1 is tilted in the direction of the arrow A from the neutral position shown in FIG. 6, first, the pressing portion 1a near the supporting shaft 1 presses the cylindrical portion 5b of the projecting portion 1a.
Consequently, the projecting portion 5 is buckled, to generate a first click feeling (stepping feeling), and also the movable contact point 5a is contacted with the fixed contact point 4a to make only the first switch S.sub.1 in the on-state. When the operating lever 1 is further tilted in the direction of the arrow A, the pressing portion 1b apart from the supporting shaft 1 presses the projecting portion 6, while the pressing portion 1a crushes the cylindrical portion 5b of the pressing portion 5.
Consequently, the projecting portion 6 is buckled, to generate a second click feeling, and also the movable contact point 6a is contacted with the fixed contact point 4b to make the second switch S.sub.2 in the on-state, that is, to make both the first switch S.sub.1 and the second switch S.sub.2 in the on-state.
On the contrary, when the operating lever 1 is tilted in the direction of the arrow B from the neutral state shown in FIG. 6, first, the pressing portion 1c near the supporting shaft 2 presses the cylindrical portion 7b of the projecting portion 7, to generate a first click feeling, and also the movable contact point 7a is contacted with the fixed contact point 4c to make only the third switch S.sub.3 in the on-state. When the operating lever 1 is further tilted in the direction of the arrow B, the pressing portion 1d apart from the supporting shaft 2 presses the projecting portion 8, to generate a second click feeling, and also the movable contact point 8a is contacted with the fixed contact point 4d, to make both the switch S.sub.4 and the third switch S.sub.3 in the on-state.
In the prior art seesaw switch described above, by tilting the operating lever 1 in one direction, the two switches are made in the on-state with the click feelings in an interlocking manner. Accordingly, in the case of using such a seesaw switch as an input switch of a power window device mounted on a vehicle, a manual action and an automatic action can be performed by the first and second switchings, respectively. For example, assuming that the direction of the arrow A is taken as an UP side and the direction of the arrow B is taken as a DOWN side, by tilting the operating lever 1 in the direction of the arrow A, it is possible to perform a manual UP during the first switch S.sub.1 is in the on-state, and to perform an automatic UP when the second switch S.sub.2 following on the switch S.sub.1 is turned on. On the contrary, by tilting the operating lever 1 in the direction of the arrow B, it is possible to perform a manual DOWN during the third switch S.sub.3 is in the on-state, and to perform an Automatic DOWN when the fourth switch S.sub.4 following on the third switch S.sub.3 is turned on.
However, for realizing such a double action, the two switches for one side, that is, the four switches S.sub.1 to S.sub.4 in total, which are operated by the tilting of the operating lever 1, are required. This brings about such disadvantages that the seesaw switch is enlarged in size, and the circuit additionally formed on each of the switches S.sub.1 to S.sub.4 is complicated, resulting in the increased cost.